1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor device including silicon carbide (SiC).
2. Description of Related Art
In accordance with the recent trend of enlarging size and capacity of application equipment, a demand for a semiconductor device for electric power, having a high breakdown voltage, a high current, and a high-speed switching characteristic has been raised.
Accordingly, many studies and developments of a MOSFET (metal oxide semiconductor field effect transistor) using silicon carbide (SiC) have been made instead of a known MOSFET using silicon. Particularly, many developments of a vertical type trench MOSFET have been made.
The MOSFET is the most general electric field effect transistor in a digital circuit and an analog circuit among semiconductor devices for electric power.
In the case of the vertical type trench MOSFET, an etching technology of forming a trench in a form suitable to a semiconductor substrate is required. Since silicon carbide has hardness and oxidation resistance that are higher than those of silicon due to a strong covalent bond material, high power etching is performed in order to overcome endurance for etching, thus causing a phenomenon where a corner portion of the trench is more deeply etched as compared to the bottom due to high power etching. Accordingly, an electric field concentration phenomenon occurs at the corner portion of the trench causing breakage of an oxidation layer, thus reducing performance of the semiconductor device.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.